More informative error message

mobile/src/main/java/be/mygod/librootkotlinx/RootServer.kt

@@ -145,7 +145,7 @@ class RootServer {
         } catch (e: Exception) {
             throw NoShellException(e)
         }
-
+        try {
             val token2 = UUID.randomUUID().toString()
             val persistence = File(context.codeCacheDir, ".librootkotlinx-uuid")
             val uuid = context.packageName + '@' + if (persistence.canRead()) persistence.readText() else {
@@ -157,6 +157,9 @@ class RootServer {
             writer.writeBytes(script.toString())
             writer.flush()
             reader.lookForToken(token2) // wait for ready signal
+        } catch (e: Exception) {
+            throw RuntimeException("Failed to launch root daemon", e)
+        }
         output = writer
         require(!active)
         active = true